Goals: Like its sister mission, Mars 6 (which arrived at Mars three days later) Mars 7 was to place a lander on the surface of Mars. The bus was to fly by the planet, taking measurements as it passed.

Accomplishments: The bus that carried the lander to Mars collected and transmitted data as it flew by the planet. But the lander's main retro-rocket failed to fire, so rather than descend, the lander flew by Mars at a distance of 1,300 km.